Means for preventing backlash in gears



May 24, 1927. 1,629,564

.1. M. WHITE MEANS FOR PREVENTING BACKLASH IN GEARS Filed 1925 2 Sheets-Sheet 1 wmv 5: INVENTOR: W6 Jssee/HJA/hfie,

7 i ATkY May 24 1927. 1,629,564

J. M. WHITE MEANS FOR PREVENTING BACKLASH IN GEARS Filed Auz. 5, 1925 2 Sheets-Sheet 2 fli Z WITNIS 5115 I IN VEN TOR W6 r L/jsee whiff, 2% W Patented May 24, 1927.

UNITED STATES PATENT. OFFICE.

arms roa raavan'rmo naomsrr m onans.

Application filed August 8, 1925. Serial No. 47,768.

My invention relates to means for preventing back-lash in gears and is especially adapted for use with timing gears of automobile engines.

The automobile industry aims to produce an' engine which runs smoothly and silently. To obtain this end, timing gears, which are most efficient for connecting the crank shaft to the cam shaft have been generally discarded because they produce an objectionable rattle.

The objects of my invention are to provide means for use with gears whereby metallic noise will be eliminated without sacrificing the clearance between the teeth and regardless of the amount of clearance produced by wear of the teeth.

' These objects, and other advantageous ends which will be described hereinafter, I attain in the following manner, reference being had to the accompanying drawings in which Figure 1 is a face view of a pairof gears having my invention appliedthereto, and

Figure 2 a section on line 22 of Figure 1 showing a part of the engine casmg.

Referring to the drawings, 1 indicates a casing, 2 a crank or driving shaft extending from thecasing, 3 a driving gear keyed to the shaft, 4 a driven ear meshing with gear 3, and 5 a cam or riven shaft keyed to gear 4 and extendin into the casing. Gear 4 has a face 6 which is slidably engaged by a face 7 of a friction gear 8 rotata 1y mounted on a hub extension 9 of gear 4. Friction gear 8 is held against face 6 of ear 4 by a spider spring 10 fastened on s aft 5 between hub extension 9 and a nut 11 on the end of the shaft. A wearing ring 12 is placed between fin ers 13 of the spider spring 10 and the 'ction gear. Friction gear 8 is of greater diameter than gear 4 and meshes with a pinion 14 keyed to the driving shaft 2. Pinion 14 is of less diameter than the driving gear 3. Friction gear 8 being in engagement with gear 4 and rotating at a slower speed will offer resistance;

to rotation of gear 4; This action will al-. ways kee the teeth of, gear 4 against the teeth of t e driving ear 3 and thus prevent the back-lash and e iminate the humming noise caused by clearance between the teeth.

In operation, driving ear 3 will operate driven gear 4 and the 5 ft 5. Pinion 14 and friction 1Egear 8 being of a different ratio from that 0 gears 3 and 4 will cause friction gear 8 to rotate at slower speed. Spring duce resistance to its rotation, but this re sistance may be produced by arran ing the gears in other ways such as by fixing gear 8 to gear 4 and rotating gear 14 relativel to gear 3, or by connecting gear 14 with gear 8 through intermediate gears. It is immaterial how the ears are arranged to cause resistance to t e movement of the driven gear so long as the frictional faces,

such as 6 and 7 move at different speeds.

While I have described my invention as taking a particular form, it will be understood that the various parts may be changed without departing from the s irit thereof, and hence I do not limit myse f to the precise construction set forth, but consider that I am at liberty to make such changes and alterations as fairly of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In combination with a driving shaft, havin a driving gear thereon, and a driven shaft aving a driven gear thereon; a. friction gear mounted to rotate relatively to the driven shaft the friction gear and the driven gear having faces frictionally enga g each other; a pinion, fixed to the driving shaft and meshmg with the friction gear, for rotatin it at a different speed from that of the riven gear, a spider spring carried by the driven shaft and adapted to hold the friction (gear in engagement with the driven gear, an a wearing ring between the spider and the friction gear.

2. In combination with a: driving shaft having a driving gear thereon and a driven shaft; a driven gear keyed to the driven e driven teeth 0 gear 4, and the come within the scope,

. speed from that of the driven gear; a. wearshaft and having a hub extension a friction ing ring engaging the friction wheel and av gear rotatable on the extension the friction splder spring carried by the driven shaft gear and the driven ear having faces 'fricand having fingers engaging the wearing 10 I tionally engaging eac 1 other; a pinion fixed ring. 5 to the driving gear and meshing with the In testimony whereof I have signed my friction gear for rotating it at a different name to this specification. J'ESSEE M. WHITE. 

